Why I fill my car when it’s not empty

STOP waiting for the low fuel light to come on before you go looking to buy.

I used to, when I had a small car with excellent fuel efficiency that ran on regular unleaded.

Then we got a big car with poorer fuel efficiency that runs on ultra premium unleaded, which is 15-20 cents a litre more expensive.

Mrs Rolfe loved the car, but I hated how much extra it was costing to operate it.

So I changed my buying behaviour.

Instead of waiting for the bowser symbol to illuminate on the dash, I now wait for the bottom of the pricing cycle. I don't have to pick the absolute bottom, just near it. That usually gives me a window of about a week in which to buy at a good price.

Once prices are in this window of opportunity it doesn't matter if my tank is near empty or half-full - I try to fill up.

I also use the NSW Government's fuelcheck app (or Motormouth in Queensland) before deciding where to buy. It is particularly useful when I am somewhere I don't know well.

Earlier this year my family and I got in the car to drive from Sydney to Newcastle.

I hadn't filled up before leaving and prices had shot up overnight.

Driving the Pacific Highway through Lindfield, Killara and Pymble - places I have no knowledge of - it appeared every station we passed was charging 26c/L more than I had seen in my own patch the day before.

My wife opened fuelcheck and used its map function. She found a BP 2km out of our way which hadn't raised prices. We took the detour and saved $18.

This report is part of #Lifehacks, a project by the News Corp Australia mastheads giving readers everything they need to know about the financial matters that impact us all - right down to scripts for securing better deals, dream jobs and more. Rolling out day by day across this week, the topics are mortgages, energy, insurance, cars, credit cards, super and salary - and you can find it all here.